OK, so somehow I managed to place second in my age group and 17th overall (!!!) at Saturday's Iron Girl Sprint Triathlon at Lake Las Vegas. I say "somehow" because I did a whole bunch of things wrong leading up to the race. Seriously, almost everything wrong (like eating a really, really gross Thai salad the night before, doing CrossFit and Spinning both days leading up to the race, to name a few). I've never podiumed a race before, and definitely didn't expect to place at this one, so I'm pretty stoked with my results. But I'm also a little bummed. Listen, hear me out: All of these dumb amateur mistakes kept me seconds [Ed. note: Literally six seconds. - RJ] from first place. The good news: these dumb amateur mistakes will be really easy for you to avoid.

Here, check the five biggest things I did wrong -- five things you should absolutely not do leading up to and during a triathlon -- so you can race your best possible race.

DON'T...

Not train in what you'll be racing in: You'll probably wear a tri kit on race day. You can either go with a onezie (which is my personal pick; they're more streamlined and you don't have to worry about pulling your pants off along with your wetsuit) or a two-piece. (Note: if you have to pee a lot, go with the latter.) Pick out whatever you're going to wear on race day weeks in advance and definitely swim, bike and run in it a few times to make sure it fits and to feel out areas that may chafe. Champion System made us (us being myself and our Fitness Editor, Marissa Stephenson) some seriously sweet custom SELF kits. But I didn't even try mine on until about eight hours before the race. Whoops. Luckily, it fit well and it didn't chafe me anywhere, but should I have had any issues arise, I'd have been SOL.

Not know what the water temperature will be: If you're doing an open-water swim, you'll probably want to wear a wetsuit. Partly because the water is usually cold, partly because it makes you buoyant. I did the Aquaphor NYC Triathlon in a full suit (sleeves and legs), so figured I'd give a sleeveless suit a whirl in Vegas, because hey, it's the desert and it's hot, right?. Wrong. The water temp was about 60 degrees. But I didn't know that when I ordered my 2XU suit. Also, I had that baby shipped right to Vegas, so the first time I even tried it on was the afternoon before the race. Again, I lucked out on the fit. So I jumped in the lake for a quick swim to get a feel for it. I immediately regretted not having full sleeves. And on race day, I never got warm in the water. During T1 [Ed. note: Non-tri folks, that's where racers transition from the swim to the bike portion of the race. - RJ], my hands were so cold I could barely get my cycling shoes on, lest the helmet strap.

Not train on the bike you're going to race on: You guys, Liv/giant is beyond awesome. They hooked me up with a Trinity triathlon bike. I know, I'm terribly spoiled. But I'm also terribly busy. So when they shipped Tanner (that's my bike's name) to NYC, I took him for a spin on the West Side Highway for about four big miles. I'm a Spinning instructor. I've done century rides and triathlons before, but I've always ridden a road bike. Tanner is a triathlon bike. It's a very different ride; a balancing act of sorts. One that requires a lot time in the saddle. My four miles was seriously, seriously inadequate. But I took my chances and had Tanner sent to Vegas. (Took him for a whopping two-mile ride when I arrived.) When it came time to race, I was a little hesitant on the first half of the ride. Vegas turned out to be a lot hillier than I expected. Plus I didn't have a bike computer, so I had NO idea how fast I was going or how many miles I was covering. But during the second half, I got a little cocky and decided to switch into aero mode. And what a game changer -- it makes the ride much faster and the bike more efficient. I pulled into T2 with no falls, no flats. Managed to average 19.4 MPH, too. But I know if I spent more time on Tanner, I'd have been more confident. And faster. And definitely a lot safer.

Not run in new shoes: I ran in shoes I had never worn before. Shocking. I wore the